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Room and pillar mining was one of the earliest methods used, [3] although with significantly more manpower. The room and pillar system is used in mining coal, gypsum, [4] iron, [5] limestone, [6] and uranium [7] ores, particularly when found as manto or blanket deposits, stone and aggregates, talc, soda ash, and potash. [8]
In deep mining, the room and pillar or bord and pillar method progresses along the seam, while pillars and timber are left standing to support the mine roof. Once room and pillar mines have been developed to a stopping point limited by geology, ventilation, or economics, a supplementary version of room and pillar mining, termed second mining or ...
Pillar. A pillar is a section of unworked coal supporting the roof. Unworked pillars of coal are left to prevent subsidence to surface features. The shaft pillar is left to prevent damage to the shafts from the workings. [1] Pit. Strictly refers to a shaft, though also used to refer to a colliery more generally. Pit brow lasses
Retreat mining is a particularly dangerous form of mining: according to the Mine Safety and Health Administration (MSHA), pillar recovery mining has been historically responsible for 25% of American coal mining deaths caused by failures of the roof or walls, even though it represents only 10% of the coal mining industry. [1]
The Morupule Colliery is a coal mine located in Palapye, Botswana, owned and operated by Debswana, a partnership between the government of Botswana and De Beers. [1] The coalfield is composed of four main seams, only one of which, the No. 1 Seam, is currently being mined, using bord and pillar mining methods.
Room and pillar mining often leads to retreat mining, in which supporting pillars are removed as miners retreat, allowing the room to cave in, thereby loosening more ore. Additional sub-surface mining methods include hard rock mining, bore hole mining, drift and fill mining, long hole slope mining, sub level caving, and block caving.
Room and pillar methods are well adapted to mechanization, and are used in deposits such as coal, potash, phosphate, salt, oil shale, and bedded uranium ores. Blast mining – An older practice of coal mining that uses explosives such as dynamite to break up the coal seam, after which the coal is gathered and loaded onto shuttle cars or ...
The Wallarah, Great Northern and Fassifern coal seams have been mined using bord and pillar mining methods. Coal is transported to the Eraring Power Station by an overland conveyor system. References